How can grafting affect yield and wine from hybrid grapevines under climatic conditions of Quebec, Canada?

Grapevine production is relatively recent in Quebec, Canada, and several challenges restrict quality grape production. Quebec’s rigorous climate and short growing season are just a couple of limiting factors in grape production and varietal selection. Rootstocks adapted to growing conditions allow producers to plant cultivars that are better adapted and more efficient in specific soil and climatic conditions. Selected scion/rootstock combinations could be better suited to growing conditions found in Quebec vineyards, thereby homogenizing vegetative growth for all vines, reducing costs associated with management and help to reach maturity and optimum berry quality. The main objective of this project was to evaluate the use of grafting as a technique to adapt hybrid vines to the cold climate growing conditions found in Quebec, Canada. Several combinations were produced using ‘Frontenac’, ‘Frontenac blanc’ and ‘Marquette’ cultivars along with 4 rootstocks (101-14 MGT, 3309 R, Riparia Gloire de Montpellier, SO4), as well as own-rooted vines. The experimental plot was planted in 2013 in gravelly-loam soil. Several parameters were observed, such as yield, berry chemistry and wine sensory analysis. Rootstock effect showed little impact on yield, but a significant impact on berry chemistry, mainly on total soluble solids and on titratable acidity. Moreover, a significant effect on wine appreciation was noticed, where use of rootstock generally increased wine quality. In Quebec, grafting hybrid cultivars is not a common practice, but it could be profitable to the producer to select rootstocks adapted to their soil and climate conditions to improve profitability.